The invention relates to an assembly of a drill bit and extension which is used in mining operations, and especially the adapter by which the drill bit is detachably mounted on the extension.
Conventional drill bit and extension assemblies have communicating bores through which dust is removed from around the drill bit during a drilling operation, or water is pumped to the drill bit to facilitate drilling of the material. The drill bit and extension are provided with aligned holes which are disposed crosswise in the two components. The adapter consists of a ball or button-type catch which is positioned in the aligned holes to hold the drill bit and extension together and a spring clip for spring loading or biasing the button catch in interlocked relation with the drill bit and extension.
The major problem is that the spring clip loses its resiliency after a period of hard and extended use, so that the adapter must be removed and replaced. The invention is designed to provide a unique adapter which has highly improved spring characteristics.
Briefly stated, the invention is in an adapter which comprises a button-type catch and a separate, cylindrical split ring for spring loading the button catch. The preferred embodiment of the invention includes a parti-cylindrical finger which extends longitudinally of the split ring and on which the button catch is initially positioned for easy insertion in the hole of the drill bit extension prior to sliding the split ring into the bore of the extension.